This invention relates to a nonimpact printer using an electrostatic recording technique such as electronic photography, and more particularly to a nonimpact printer which is suitable for bicolor printer.
Recently, numerous nonimpact printers have been developed which make effective use of the high printing speed of an electrostatic recording system such as electronic photography. Such a nonimpact printer generally has the following constitution. An electrophotographic photosensitive drum is used and the surface of the drum is uniformly corona charged under dark conditions by a corona charger. Thereafter, through an exposure process, latent images of a rectangular lattice for chits and/or repeated patterns are usually formed on the surface of the drum and the latent images according to the information as the output of an electronic computer are formed on the surface of the drum through the laser light exposure. By developing the thus formed latent image with toner is formed a toner image which is to be transferred to a printing medium to obtain a print.
With such a print, e.g. a document, if the rectangular lattice and the calculated value or data are printed in different colors, the printed content is easily read and understood, as is experienced usually.